Market adoption of wireless LAN (WLAN) technology has exploded, as users from a wide range of backgrounds and vertical industries have brought this technology into their homes, offices, and increasingly into the public air space. This inflection point has highlighted not only the limitations of earlier-generation systems, but also the changing role that WLAN technology now plays in people's work and lifestyles, across the globe. Indeed, WLANs are rapidly changing from convenience networks to business-critical networks. Increasingly users are depending on WLANs to improve the timeliness and productivity of their communications and applications, and in doing so, require greater visibility, security, management, and performance from their networks.
Admission control is a technique used in bandwidth-constrained networks or over bandwidth-allocated links to manage the effects of congestion. In wireless local area networks (WLANs), wireless clients may request bandwidth for Quality of Service (QoS) services via a traffic specification (TSPEC) request according to the IEEE 802.11e specification or the Wi-Fi Alliance's Wi-Fi Multimedia (WMM) specification. In response to this request, a wireless access point will attempt to admit the QoS flow if over-the-air (OTA) bandwidth is available. A policy configured by a system administrator permits this operation. One characteristic of admission control is that a wireless access point will continue to accept and admit new QoS flows, but only until the OTA bandwidth is used up or until the OTA usage reaches a pre-defined threshold set by the system administrator. Once this occurs, subsequent requests for OTA bandwidth are denied.